After some days of my vacation, my Fedora workstation was not able to boot. I stuck in the grub rescue shell, something was wrong with my MBR-recoord. There was a wrong UUID.
As I tried to update grub (command update-grub) – I stuck again – command not found! This is a Debian/Ubuntu specific command and is not available here.
This is a update-grub in Fedora way:
grub2-mkconfig -o /boot/grub2/grub.cfg
And finally the MBR installation:
grub2-install --recheck --no-floppy /dev/sda